| 摘要 |
<p>An oxide layer (22) is formed on material defining and surrounding an emitter window (100) . The technique comprises depositing a non-conformal oxide layer (24) on the surrounding material and in the emitter window (100) , whereby the thickness of at least a portion of the oxide layer (24) in the emitter window (100) is smaller than the thickness of the oxide layer (24) on the surrounding material outside the emitter window; and removing at least a portion of the oxide layer (24) in the emitter window (100) so as to reveal at least a portion of the bottom of the emitter window whilst permitting at least a portion of the oxide layer (24) to remain on the surrounding material. The technique can be used in the manufacture of a self-aligned epitaxial base BJT (bipolar junction transistor) or SiGe HBT (hetero junction bipolar transistor) .</p> |
